Protect PDF
Lock a PDF with a password using AES-256 encryption, so only people who know it can open the file. Done in your browser; the file and password stay private.
Runs in your browser. Nothing is uploaded.
About the Protect PDF
A password on a PDF keeps its contents private when it travels by email, sits in a shared folder or is uploaded somewhere you do not fully control. Payslips, bank statements, medical letters and ID scans are common examples.
The tool encrypts the whole file with AES-256, the strongest standard PDF encryption, which every modern PDF reader supports. Anyone opening the file is asked for the password. Encryption happens in your browser with qpdf, an open-source PDF tool, so neither the document nor the password is sent anywhere. Send the password by a different route from the file, for example by phone or text message, so one intercepted message is not enough.
How to use the Protect PDF
- 1
Drop a PDF onto the page or choose one from your device.
- 2
Type a password twice. Twelve or more characters is much harder to guess.
- 3
Press “Protect and download” to save the locked copy.
Examples
report.pdf with a password of 4 characters or morereport-protected.pdf, encrypted with AES-256report.pdf with the password abcError: Use a password of at least 4 characters.Good to know
- A forgotten password cannot be recovered, by us or anyone else. Keep an unprotected copy if you might need one.
- Very old PDF readers that do not support AES-256 cannot open the file.
- PDFs that already have a password must be unlocked first.
Frequently asked questions
How secure is it?
AES-256 is the strongest encryption in the PDF standard. In practice, security depends on the password: a long, unusual password or passphrase is very hard to break, a short common one is not.
Can I stop people printing or copying instead?
Not yet. Print and copy restrictions are easy to bypass in many readers, so this tool sets an open password, which actually keeps the contents private.
Is my password stored?
No. It is used in your browser to encrypt the file and is then forgotten. It is never sent or saved.
Are my files uploaded?
No. Files are opened and processed in your browser, in a background thread. Nothing is uploaded, so the tool also works for confidential documents.
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